DECODE(base_expr,
compare_1, value_1,
compare_2, value_2,
…
compare_i, value_i,
default)
The DECODE function is similar to a sequence of built-in operators IF-THEN-ELSE. The basic expression (base_expr) is successively compared with the expressions compare_1, compare_2,…,compare_i. If the basic expression corresponds to the i-th point of comparison (compare_i ), the i-th value is returned (value_i). If the basic expression does not match any of the points the default value is returned. Comparison expressions are considered by turn. If the match is fount, other expressions are not compared. If the default value has not been specified, NULL is returned.
DECODE(PERSON,'F','1','M','-1',0) <> 0
The PERSON field should contain only the symbols F and M.
NVL(expr1, expr2)
The NVL function returns the expr2 value if the expr1 contains the NULL value, otherwise it returns expr1.
NVL(ID_PARENT, ID_CHILD) IS NOT NULL
The ID_PARENT and ID_CHILD cannot both contain the NULL value at the same time.
CALL_DATE(proc[, param])
The CALL_DATE function returns a date which is the result of the procedure PROC registered in the base. Param is one or several expressions (an optional parameter) that are regarded as a parameter when the procedure PROC is called.
DT = CALL_DATE(PROC_1)
The date in the DT field should match the date returned by the procedure PROC_1.
CALL_NUMBER(proc[, param])
The CALL_NUMBER function returns a number which is the result of the procedure PROC registered in the base. Param is one or several expressions (an optional parameter) that are regarded as a parameter when the procedure PROC is called.
NUM = CALL_NUMBER(PROC_1)
The value in the NUM field should match the value returned by the procedure PROC_1.
CALL_VARCHAR(proc[, param])
The CALL_VARCHAR function returns a string which is the result of the procedure PROC registered in the base. Param is one or several expressions (an optional parameter) that are regarded as a parameter when the procedure PROC is called.
STR = CALL_VARCHAR(PROC_1)
The string in the STR field should match the string returned by the procedure PROC_1.
See also: